The present invention relates to an omnidirectional antenna assembly having a wide range of antenna gain and are particularly applicable to satellites, etc. More particularly, the present invention is concerned with an omnidirectional antenna assembly whose gain range is increased by combining a reflector of a four-element whip antenna with another reflector (e.g., a reflector constituting part of a satellite body or a reflector of a biconical antenna or like antenna) which serves as a second antenna in relation to the four-element whip.
A four-element whip antenna is an omnidirectional antenna which is extensively used with satellites, etc. The four-element whip antenna has a reflector which is spaced from and electrically connected to another reflector by a feeder cable. A problem with these antennas is that the primary radiation from one of the reflectors and the secondary reflection (reflected wave) from the other reflector interface with each other, with the result that at angles .theta. of radiation pattern adjacent .+-.90.degree., great ripples are developed and the level of radiation is sharply lowered to reduce the range of availabe gain. Biconical antennas, the combination of a four-element whip antenna and a biconical antenna, and the like are also useful as omnidirectional antennas, but they have the same problem as the four-element whip antenna.